Police learned of the 2:02 p.m. shooting after both victims walked into Richmond University Medical Center's emergency room with gunshot wounds.

The eyewitness told police the shooting occurred after he intervened in a physical altercation between a friend of his and a heavyset stranger. After stepping out of his car to defend his friend, the witness said someone hit him in the head, according to police. It's unclear who delivered the blow or how it was delivered.

Following the blow, the witness said he saw another man -- not the one feuding with his friend -- fire several rounds into a crowd.

Tart was arrested Monday morning, and is slated to be arraigned Tuesday in Stapleton Criminal Court on two counts each of second-degree attempted murder, second-degree criminal possession of a weapon and second-degree assault, and a single count of criminal possession of a firearm, according to information from District Attorney Daniel Donovan's office.